1. Field of the Invention
This invention relates to a bookbinding device which provides a booklet from a bundle of recording sheets.
2. Description of the Related Art
For example, in the bookbinding of a booklet such as a notebook, a sketchbook, and a picture book, a plurality of binding holes are continuously formed at the end of the booklet, and a coiled binder is inserted into the binding holes from the end while being rotated.
Meanwhile, for example, an electrophotographic image-forming apparatus has high-speed performance, multiple functions, and network functions, and when the image forming apparatus is connected with a high capacity sheet feeder and a high capacity stacker, the application as a printer is expanded.
As bookbinding processing of a printed matter printed by the printer, there has been known a bookbinding processing that, for example, a U-shaped binding needle is inserted into one end of a bundle of accumulated printed sheets, and both ends are folded inward, whereby the one end of the sheet bundle is bound to provide a booklet (refer to Japanese Patent Application Laid-Open No. 10-198105).
When the coiled binder is inserted into the binding holes from the end while being rotated, it takes time for the insertion, and it is difficult to insert the binder into a proper position in the bookbinding.
Meanwhile, in the bookbinding device disclosed in Japanese Patent Application Laid-Open No. 10-198105, the U-shaped binding needle is inserted on the sheet post-processing apparatus side, and both ends are folded inward, whereby one end of the sheet bundle is bound to provide a booklet. Therefore, a folding defect easily occurs, and it is difficult to realize reliable binding. Meanwhile, when an image-forming system includes a sheet post-processing apparatus, if a failure occurs in the sheet post-processing part, image recording should be performed again from the beginning.
When the number of recording sheets is large, the thickness of the sheet bundle is increased, so that it is difficult to insert the U-shaped binding needle into the sheet bundle and fold both ends inward. In addition, a folding defect easily occurs, and thus, according to the thickness of a sheet bundle, the sheet bundle cannot be bound to be provided as a booklet.